Mixing the immiscible through high-velocity mechanical impacts: an experimental and theoretical study

In two-component metallic systems, thermodynamic immiscibility leads to phase separation such as in two-phase eutectic compositional alloys. The limit of the immiscibility of component elements under non-equilibrium conditions have been explored, but achieving complete miscibility and formation of single phase microstructures in eutectic alloys would be unprecedented. Here we report that during low-temperature ball milling that provides high energy impact, complete mixing of phases can occur in immiscible Ag-Cu eutectic alloys. From combined theoretical and experimental studies, we show that impact can produce solid solutions of Ag-Cu nanoparticles of eutectic composition. Our results show that phase diagrams of low dimensional materials under non-equilibrium conditions remain unexplored and could lead to new alloy microstructures drastically different from their bulk counterparts.